The Setting Up Mailsmith section describes how to set up Mailsmith to filter
your mail using SpamSieve.

Make sure that you are using version 2.3.1 or later of Mailsmith.

Make sure that Use SpamSieve is checked in the preferences. If that
option is disabled:

Make sure you have only one copy each of Mailsmith and SpamSieve
installed. If there are any old versions in the trash, empty the
trash.

Launch SpamSieve directly from the Finder, by double-clicking its
icon. (Do not use the Dock icon or an application launcher.)

Launch Mailsmith (again, by double-clicking its icon).

Open Mailsmith’s Preferences window, and verify that the Use
SpamSieve option is enabled.

If you are using the Leave it in “(incoming mail)” option, make sure
that a deposit or transfer filter isn’t acting on the spam messages
before your spam filter can.

To test the connection between Mailsmith and SpamSieve, select a message
and choose Recalculate Spam Score from Mailsmith’s Message menu.
Then choose Open Log in SpamSieve and verify that a “Predicted” entry
for that message was added to the log.